1. Field of the Invention
The present invention relates to data communication systems. More specifically, the present invention is directed to a data communication system using redundant data signal carrying conductors for providing a fail-safe data communicating path between a central station and a remote station.
2. Description of the Prior Art
The field of process control usually involves the gathering of data representing process variables from remote and environmentally hazardous locations and the transmission of this data to a central station. The use of data signal carrying cables, or conductors, in data communication links between the central station and such locations imposes upon the process control system, the added hazard of a loss of a data communication link by way of damage to a data cable. In many process control systems, e.g., chemical plant systems, the loss of a data communication link could lead to disastrous consequences in the event of a loss of control in contemporary automated process control systems. In order to attempt to avoid such a loss of a vital data communication link, a prior art solution has been to extensively protect the data cables against forseeable hazards. Such protective enclosures are often effective to make the control system impractical as well as uneconomical and cannot protect the data cables against all hazards. Accordingly, it is desirable to provide a data communication system having means for automatically maintaining data communication links to prevent a loss of data between a remote location and a central station.